Methods, devices, and systems for obesity treatment

ABSTRACT

In one aspect, a gastric balloon structure includes multiple isolated non-concentric inflatable chambers and a valve system for introducing fluid into each chamber, where the structure assumes, upon inflating, a curved shape conforming to a natural three-dimensional kidney shape of the gastric cavity.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of priorityfrom U.S. patent application Ser. No. 14/971,845, filed Dec. 16, 2015and issued Apr. 14, 2016 as U.S. Pat. No. 9,456,915 entitled “Methods,Devices, and Systems for Obesity Treatment.” Application Ser. No.14/971,845 is a continuation of and claims the benefit of priority fromU.S. patent application Ser. No. 11/282,224, filed Nov. 18, 2005, whichis a continuation-in-part of application Ser. No. 11/170,274, filed onJun. 28, 2005 and issued Dec. 6, 2011 as U.S. Pat. No. 8,070,807entitled “Wireless Breach Detection”, which was a continuation in-partof application Ser. No. 11/122,315, filed on May 3, 2005 and issued Nov.29, 2011 as U.S. Pat. No. 8,066,780 entitled “Methods for Gastric VolumeControl”, and claims the benefit under 35 USC § 119(e) of priorprovisional application No. 60/629,800, filed on Nov. 19, 2004, the fulldisclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to medical apparatus andmethods. More particularly, the present invention relates to implantabledevices and methods and systems for detecting their malfunction orfailure or impending malfunction or failure.

All implants of devices, especially those indicated for long term use,in the human body are highly regulated and must meet certain safetyrequirements. One such requirement is biocompatibility of the materialsused in the construction of the device in the event they come intodirect contact with body tissues and fluids. Even if the material isbiocompatible, the contact with body tissues and fluid could result indiminished performance or malfunction esp. in devices with electroniccomponents. It is known that when a device is implanted in the body, thematerials forming the cover and structural elements of the devicedegrade and fatigue over time. It is also well known that excessivehandling during implantation or even normal, repetitive movements couldstress the structural integrity of the device. Failure of the structuralintegrity of the device or its covering, which eventually happens,causes the contents of the device, which heretofore were confined in theinterior of the device, to be in contact with the surrounding tissuesand their secretions. Therefore, it would be desirable to detect or topredict such an event before any potentially harmful contents come incontact with the surrounding tissues, before tissue secretions leak intothe interior of the device resulting in malfunction, or before thecontent itself suffers a malfunction.

Prosthetic devices implanted in numerous locations in the body areprevalent in medical practice. Many of these prostheses are designed toassume the structural shape of the body part yet are soft and havesimilar flexibility to approximate the look and feel of normal humantissue. A common use has been for reconstructing the normal contour,improving the shape, and/or enlarging the size of the human breast. Themost common breast prosthesis is a soft elastomeric container made ofsilicone rubber which is filled or “inflated” with a liquid or gel,typically a saline solution or a silicone gel, or a combination of suchfilling materials. Typically such prostheses are surgically implanted tofit underneath the skin of the body either between the chest wall andthe mammary gland or in place of the mammary gland following amastectomy. The ideal result after implantation is to achieve thecontours and tissue characteristics of a natural breast, and prostheticdevices filled with silicone gel have been found to produce the bestcosmetic result. Hence, silicone gel breast implants are the devices ofchoice in locations where they are approved.

Degradation and fatigue of the silicone rubber container of such breastimplants, however, can lead to perforations, tears, ruptures, and seamseparations, resulting in the leakage of filling materials to thesurrounding tissues. Leakage from a saline filled device is usuallyharmless as the solution, if uncontaminated, is absorbed. Leakage fromthe preferred silicone gel filled device is much more problematic.Bleeding of gel at the surface is believed to contribute to thedevelopment of capsular contracture, a scarring condition thatcompresses the implanted device from a soft, natural profile into arigid, spherical shape. More serious is the migration of leaked siliconegel to other parts of the body such as the lymph nodes and major organswhere it becomes unremovable. Consequently, silicone gel has beenimplicated in many health problems including connective tissue diseases.This risk increases with the length of time the device is implanted.

The problem is exacerbated by the fact that leakage of silicone gel isnot easily detected and the rupture of the device cannot be predicted.Unlike saline filled devices where rupture and leakage results indeflation over a short period of time and readily discovered by thepatient, silicone gel tends to leak slowly and can go unnoticed foryears. Often the rupture is discovered only upon removal of the devicefor another reason. The only noninvasive method currently sensitiveenough to detect such an event reliably is an MRI scan. To monitor theintegrity of a silicone gel device by regularly scheduled MRI scans iscost prohibitive. Consequently, the use of silicone gel filled breastprostheses is now highly restricted by regulatory authorities.

Gastric balloons are another type of implantable, inflatable prosthesiswhich is subject to failure from breach of the wall. Gastric balloonsare typically introduced through the esophagus and inflated in situ inorder to occupy a significant volume within the stomach. While gastricballoons are typically inflated with saline or other non-toxic materialswhich are benign if released into the stomach, the balloon structureitself is hazardous if accidentally deflated since it can pass and causeobstruction of the pyloric valve or the intestines distal to the pyloricvalve. Any such obstruction is a medical emergency.

The problem is not limited to inflatable devices. Many implanteddevices, e.g., cardiac pacemakers, contain electronic circuits and haveinsulated wires or leads that sense or deliver signals at certain pointsin the body. For example, the covering or insulation could deteriorateover time or tear in response to normal body movements. Body fluids fromthe surrounding could then leak into the circuitry, either as a liquidor vapor, causing disruption of signals. Or the lead could break at anypoint or detach from the connector to the device. Another class ofimplanted devices involves a closed vessel system conveying fluidsleading from a part of the device or a part of the body to another partof the body, such as a shunt conveying blood or cerebrospinal fluid. Thecatheter or reservoir in the system could tear or break leading to theleakage of material out of the catheter to an unintended part of thebody or leakage of body fluids into the catheter causing contamination.Yet another class of devices, which depend on solid objects for functionor structural support, could fail from fracture or dislocation. Thesefractures can start as a hairline from repeated mechanical stress fromuse and progress to a complete fracture. Dislocations start with aloosening of the structure(s) holding an object in place and progress toa complete dislocation.

For these reasons, it would be desirable to provide apparatus andmethods to detect or predict an actual or potential wall breach whichcan lead to leakage of the filling contents of breast implants, gastricballoons, catheters, reservoirs, and the like or an actual or potentialdisruption of an electronic circuit in cardiac pacemakers orneurostimulators or the like or an actual or potential stress fractureor dislocation in the case of solid components in prosthetic devices orthe like. It would desirable further to monitor remotely the structuralintegrity and presumed functional status of a device without activatingthe function after device implantation in the case of cardiacdefibrillators or without directly applying stress to the monitored partin the case of solid components. Prompt removal of such devices uponbreach or imminent breach would avert most, if not all, of the ensuingproblems including catastrophes. The methods and apparatus willpreferably be adaptable for use in any structural design of the devicewithout adversely affecting its structure or, in the case of breastimplants, the final cosmetic result, and further be applicable to solidand rigid body implants containing electronic components such aspacemaker and defibrillator canisters and leads and to solid bodyimplants such as prosthetic heart valves or orthopedic devices. It wouldbe further desirable if the breach or imminent breach of the device weredetectable to the patient in an easy, rapid, and reliable fashionoutside of a medical facility or at home. Additionally, it would bebeneficial if the system were able to monitor the device non-invasivelyon a frequent basis over the life of the device without incurringsignificant additional cost for each diagnostic event. At least some ofthese objectives will be met by the inventions described hereinafter.

2. Description of the Background Art

Leakage detection is described in U.S. Pat. No. 6,826,948 and publishedapplications US 2004/0122526 and US 2004/0122527. Breast implants andmethods for their use are described in U.S. Pat. Nos. 6,755,861;5,383,929; 4,790,848; 4,773,909; 4,651,717; 4,472,226; and 3,934,274;and in U.S. PubL Appln. 2003/163197. Gastric balloons and methods fortheir use in treating obesity are described in U.S. Pat. Nos. 6,746,460;6,736,793; 6,733,512; 6,656,194; 6,579,301; 6,454,785; 5,993,473;5,259,399; 5,234,454; 5,084,061; 4,908,011; 4,899,747; 4,739,758;4,723,893; 4,694,827; 4,648,383; 4,607,618; 4,501,264; 4,485,805;4,416,267; 4,246,893; 4,133,315; 3,055,371; and 3,046,988 and in thefollowing publications: US 2005/0137636; US 2004/0215300; US2004/0186503; US 2004/0186502; US 2004/0162593; US 2004/0106899; US2004/0059289; US 2003/0171768; US 2002/0099430; US 2002/0055757; WO03/095015; WO88/00027; WO87/00034; WO83/02888; EP 0103481; EP0246999;GB2090747; and GB2139902.

BRIEF SUMMARY OF THE INVENTION

The present invention provides systems and methods for detecting partialor complete breach in the exterior wall of an implantable device, suchas an inflatable, implantable prosthesis of the type where a wall atleast partially surrounds a fluid medium, liquid or air, in one or moreinflatable compartments. The walls of inflatable devices will usually benon-rigid, either elastic or non-elastic. Other implantable devicessubject to exterior structure breach include metal and plastic (polymer)devices which may comprise rigid-walled casings or housings, such aspacemakers, implantable defibrillators, neurostimulators, insulin pumps,reservoirs, devices having flexible housings such as elastomericreservoirs containing with naturally collected or pre-filled fluids orinsulation or other coverings formed over the electrically conductivecore of electrical leads, electrical connectors (e.g., plugs), and thelike. Implantable devices subject to stress fracture in solid functionalcomponents include artificial joints, prosthetic heart valves, and thelike. These and other devices may contain potentially bioincompatiblematerials, such as batteries, circuitry, synthetic chemicals, and thelike. While the implementation of these systems and methods will bedescribed in detail in connection with inflatable devices such as breastimplants and gastric balloons and with solid core devices such aselectrical leads, it will be appreciated that the principles may beapplied to other inflatable prostheses, such as penile implants, tovessel systems containing or conveying fluids, to electronic and otherdevices having solid internal structural or functional components. Thesystems of the present invention are incorporated into at least aportion of the wall of the wall or covering of the inflatable prosthesisor other device or coupled to the electronic circuitry or embedded inthe solid component itself and provide for or enable the emission ortransmission of a detectable radio-frequency or other electronic signalupon breach or partial breach of the wall or the structural integrity ofthe component. As used hereinafter, the term “breach” will refer to anypartial or full penetration of the structure of the wall or covering aswell as to other mechanical disruption of a solid part of the devicewhich could initiate or lead to the contact of materials inside the wallor covering or the solid component itself with tissues or body fluidsoutside the device. Such breach signifies a compromise or a threateningcompromise to the integrity of the device.

The signal emission system of the present invention preferably comprisesa signaling circuit having one or more components which become exposedto an exterior or interior environment surrounding or within theprosthesis or other implantable device upon breach or partial breach ofthe wall or covering, wherein such exposure enables, disables,energizes, and/or changes a signal which is emitted by the system. Inparticular, the breach may act like a switch to close or open a regionwithin the signaling circuit to cause, enable, disable, or alter thesignal emission. Alternatively, the exposure of the circuit and/orinternal structure to the interior or exterior environment may result ina change in impedance, capacitance, inductance or other detectablecircuit characteristics that can trigger or modify the signal emitted.

In a first embodiment, the component of the signaling circuit willgenerate electrical current when exposed to a body fluid and/or aninterior medium within the device upon breach or failure of the exteriorstructure. Body fluids such as blood, cerebrospinal fluid, lymph fluid,and the like, are naturally conductive, i.e., contain electrolytes. Theinterior medium, such as an inflation medium, can be selected to beelectrically conductive, e.g., comprise or consist of saline or otherbiologically compatible electrolytes and salt solutions. In such cases,the generated electrical current can power an unpowered transmissioncomponent to emit the signal. Alternatively, the power can alter asignal which has already been continuously or periodically emitted bythe signaling circuit. In the latter case, the signaling circuit mayrequire a separate source of energy, such as a battery or circuitcomponents which are placed on the exterior or interior of the wall sothat they are always exposed to fluids to provide for currentgeneration.

Alternatively, the circuit components may include spaced-apartconductors which are electrically coupled to the signaling circuit to“close” the signaling circuit to permit current flow when exposed to abody fluid and/or device contents by a wall breach. Alternatively, thecircuit may be altered, enabled or otherwise modified by a sufficientflow of electrolytes to enable, interpret, disrupt, or modify a signalemission. The circuit components may include spaced apart conductorswhich are coupled to the signaling circuit to detect a change inresistance, capacitance, impedance, or voltage. Since the breach couldbe small and intermittent as it starts, it can be difficult to detect asa flow but the cumulative gain or loss of the electrolytes from thecontents or surrounding body fluids could cause a change in theresistance, capacitance, or impedance across the conductors.Alternatively, the detection circuit is closed and the contact of thecontents or the body fluids with the conductors could cause a break,disruption, or change in the functioning of the circuit. In theexemplary embodiments described below, the conductors may comprisemeshes, films, or other relatively large surface areas covering most orall of the wall so that breach at any point in the wall will provide theintended electrically conductive bridging between the conductors. Thecoupling of the conductors may also cause, alter, or enable a signalemission to alert the patient of the breach or potential breach. Thespaced-apart conductors can have anyone of a variety of shapes orconfigurations, continuous configurations, such as plates and films, ordiscontinuous configurations, such as lattices, meshes, and the like,can be placed in various locations, preferably near interior portions ofthe device where body fluids will pool to enhance sensitivity andreliability of the detection.

Alternatively, the detection and signaling circuit may comprise at leasttwo conductors coupled to a third conductor which is part of thefunctional circuitry or is embedded in the solid component of the deviceor is the solid component itself. In the event any of the conductors,and the third, functional conductor in particular, is fractured, evenintermittently, a circuit is broken thereby causing a signal alterationby the signaling circuit to alert the patient of the breach or potentialbreach. The detecting conductors can have any one of a variety of shapesor configurations, including continuous configurations, such as platesand films, or discontinuous configurations, such as lattices, meshes,braids, fabrics, and the like, and can be placed in various locations,preferably spanning parts of the device where fractures are prone inorder to enhance sensitivity and reliability of the detection. More thanone of these couplings could be made in any configuration or location ona device to determine the site of the breach.

The signaling circuit can be active or passive. In a preferredembodiment, the signaling circuit will comprise a passive transponderand antenna which are adapted to be powered and interrogated by anexternal reader. Such transponder circuitry may conveniently be providedby using common radio frequency identification (RFID) circuitry wherethe transponder and tuned antenna are disposed on or within a protectedarea in the prosthesis and connected to remaining portions of thesignaling circuit. Passively powered circuitry is particularly preferredin devices with on board batteries where the amount of energy stored inthe battery generally determines the functional product life. Theantenna and transponder could be located in close proximity to thedetection circuitry or placed elsewhere in the device or another part ofthe body. For example, by connecting the transponder circuitry to “open”conductors which is closed in the presence of body fluids and/orinflation medium, the signal emitted by the transponder uponinterrogation by an external reader may be altered. Thus, the patient ormedical professional may interrogate the prosthesis and determinewhether or not the prosthesis remains intact or the threat of animpending breach exists. This is a particularly preferred approach sinceit allows the user to determine that the transponder circuitry isfunctional even when a breach has not occurred.

The present invention further provides methods for signaling breach of awall or covering of an inflatable prosthesis, electronic prosthesis,solid prosthesis, electrical cable, or the like. Usually, signalingcomprises generating an emission by closing a signaling circuit when thewall or part of the device is at least partially breached. Usually aflow of electrolytes occurs when the wall or part of the device is atleast partially breached, thereby closing the signaling circuit. Todetect a near complete or complete fracture in solid components,generating an emission may comprise opening a signaling circuit when thewall, covering, or other part is substantially breached or generating anelectrical current when the part is substantially breached. Theparticular signaling circuits and transmission modes have been describedabove in connection with the methods of the present invention.

The signaling system of the present invention can be designed tofunction using any one of a variety of algorithms to notify the patientin a simple, unequivocal fashion. For example, in a toggle algorithm,the transmitter is either on in the static state or preferably off inorder to reduce the need for power. Upon direct contact between theconductors and the body fluids and or device contents, the now closedcircuit cause the transmitter to turn the signal off or preferably on tobe able to send a wireless signal on a continuous basis. The wirelesssignal or lack thereof depending on the algorithm is recognized by thedetector to notify the patient that the integrity of the device iscompromised.

Alternatively, the algorithm could be based on time, amplitude,frequency, or some other parameter. For example, the transmitter maysend a wireless signal at a predetermined time interval in its staticstate. The detector recognizes the length of the interval as normal andthe existence of the signal as the system in working order. Upon directcontact with the body fluids or device contents by the probes, thetransmitter is enabled to send the same signal at different timeintervals or a different signal, which is recognized by the detector tonotify the patient that the integrity of the device is compromised. Thelack of a signal is recognized by the detector to notify the patient ofa detection system malfunction and potential compromise of the integrityof the device.

Optionally, more than one probe or more than one type of probe may beplaced internally in different parts or components in the device so thatthe particular part or component which failed may be identified based onwhich probe was activated. The transmitter would send different signalsfor the receiver to display the source of the failure.

The internal probe could be of any shape and is disposed in the interioror preferably in the wall or covering of the device. The preferredconfiguration is a fine lattice or continuous film of the detectionmaterial embedded in the wall or in between layers of the wall coveringthe entire device, thereby conforming to the shape of the device. Such aconfiguration optimizes the performance of the system in detectingfailures early. As the site of the tear or rupture cannot be predicted,the probe would be unlikely to miss detecting the breach by covering theentire device.

Compromise of the device typically starts with a somewhat linear splitor tear in surface of the device wall or covering from mechanicalfatigue or handling damage. As the split propagates, it will expose moreand more lines of the lattice or area of the film to the body fluids andor device contents. Consequently, as the size and seriousness of thebreach increases, the probability of detection increases. Embedding thedetection material in the covering such as the wall of the balloonfurther enables detection before a full breach of the entire thicknessof the device wall.

The detection material could be any metal, polymer, fiber, ingredient,or combination thereof, with or without any coating that can generate anelectrical charge or enable flow of electric current when in contactwith the body fluids or device contents. For example, an electricalcharge could be generated from a non-toxic chemical reaction when thelattice exposed underneath a tear comes in contact with the bodysecretions. Flow of electric current could be enabled when two ends ofan electric circuit hitherto physically separated by electricallynon-conductive material in the covering or a structural element of thedevice are in contact with electrolytes in the body secretions when theelectrically nonconductive material is compromised. For example, acharged lattice is embedded in the wall separated by silicone rubberfrom the ground probe on the external surface of the device. When thelattice is exposed to the electrolytes in the body fluids in the eventof a tear, the circuit is closed. Alternatively, the lattice and groundcould be separate from each other but interlaced in the wall of thedevice. Preferred materials include non-corrosive, biocompatible metalsand elastomers, inks, or the like which contain electrically conductiveparticles.

The transmitter can be a simple wireless signal generator triggered byan electric current or preferably a transponder using thewell-established RFID technology, i.e., produces a wireless signal whentriggered by an interrogating signal. The electric charge generated orthe electric current enabled by the probe in contact with the bodyfluids or device contents changes the logic state thereby enabling thetransmitter to emit or causes it to emit a wireless signal. Typically,the transponder is powered by the interrogating radio frequency signalso that no power source of its own is required. Alternatively, thetransmitter could be powered by a micro battery or by the electricalpower generated by a chemical reaction. For protection from degradationby an acidic and electrolyte solution and become potentially toxic, thetransmitter or transponder circuit is encased in a highly resistantmaterial, such as silicone rubber or stainless steel. The transmitter ortransponder circuit can be placed on the exterior, embedded in the wall,or preferably in the interior of the device for shielding from chemicaldegradation and mechanical stress. It can be placed in any orientation,preferably in the plane where the antenna is most sensitive and thetransmitter is most effective in sending and receiving signals throughbody tissue overlying the device.

The wireless signal from the transmitter is recognized by a separatedetector, typically external to the body. The detector could be simply areceiver tuned to the transmitter's signal or, preferably, a combinationof both a transmitter of a signal to interrogate the transponder and areceiver to distinguish the different signals from the transponder. Thedetector is preferably powered by batteries and portable enough to beworn on a wristband, necklace, or belt or can be placed convenientlynear a place where the patient spends most of his time. Upon receiving asignal that a breach has occurred, the detector will alert the patientto seek medical assistance or alert medical professionals directlythrough other devices, such as Bluetooth linked to an autodialtelephone. The alarm could be auditory, such as beeping sounds, visual,such as flashing LED's or a LCD display, sensory, such as vibrations, orpreferably a combination of any or all of the above.

Optionally, the detector could have different auditory, visual, sensory,or different combinations to identify the source of the detected breach,especially with more than one probe or more than one type of probe. Forexample, LED's of different colors or different sounds could be used.The alarm could further indicate the seriousness of the breach. Forexample, when multiple probes detect a breach, the volume of the alarmwould increase to a higher level.

In the case of electronic implantable devices, such as pacemakers anddefibrillators, the devices will be subject to failure due to intrusionof body fluids through breaches, particularly at the seams and leadconnections. Thus, the detector circuit components described above couldbe located within the device canister near those seams and connectors atrisk of failure so that initial penetration of fluids could be detectedbefore sufficient amount of fluids, liquid or vapor, has entered tocause failure of the device.

In the case of electrical leads used in electronic stimulation devices,a breach in the insulation and a breach in the conductor can both bedetected. The embodiments described above are particularly suitable fordetecting a breach in the covering insulation from wear and tear.Usually this breach will precede and can serve as a sentry for a breachin the conductor. A breach in the conductor without a breach in theinsulation can be detected by a closed circuit formed by two conductingprobes, one coupled to the conductor near its proximal end and the otherat its distal end. Any fracture or disruption of the current flow in theconductor, whether made of a metal, elastomer, or gel, between the twopoints will result in “opening” the circuit. An opening will change thelogic state of the detection circuit and enable the transmitter to emitor causes it to emit a wireless signal. The detection and transmittingcircuitry could be attached to any part of the lead or is in its ownseparate housing connected to the lead by the conducting probes. Thus,the detection and transmitting circuitry could be placed in a preferredorientation where normal body movements would not cause any sharp anglesin the conductors and an area away from sites where wear and tear aremore prone.

In the case where electrical leads are coupled to another conductor suchas the connector outside the canister containing the functioninghardware and software, the principles and methods can detect detachmentof the lead. In this embodiment, one probe is electrically coupled tothe male and another probe to the female side of the connection. Whenthe lead is detached from the connector, the circuit is thereby “opened”and detected as a breach.

In the case of solid devices, such as artificial joints or heart valves,the conductors are embedded in the device components prone to failure.The detection and transmitting circuitry could also be embedded in thedevice or placed in an area away from sites where wear and tear are moreprone or signal transmission could be adversely affected.

In one aspect, the present disclosure provides improved gastric balloonsand methods for their deployment and use. The balloons may have anoverall volume or displacement selected to leave a residual volume inthe proximal area of the stomach in the range from 10 ml to 100 ml,usually from 20 ml to 40 ml. As discussed in detail below in someembodiments, the volume may be adjustable to optimize treatment onindividual patients. The gastric balloons may be designed to conform tothe natural shape of the gastric cavity while maintaining the normalfunction of the stomach. The balloon may have a crescent or “kidney”shape to align the balloon wall against the greater and lessercurvatures of the stomach, an oval cross section to conform to the shapeof the cavity in the sagittal plane, and delineate a space proximallyfor the collection of ingested food and another space distally foractive digestion.

In one aspect, the gastric balloons include at least two principalstructural components. The first principal structural component is anexpandable scaffold which helps define a shape conforming to a gastriccavity, typically a crescent or “kidney” shape, when expanded. Thescaffold may be self-expanding, e.g. formed from a shape memory metal orshape memory polymer, or may be inflatable with an incompressible fluid,such as saline, water, oil, gel, or other liquid, gel, slurry, solution,or the like. Use of an incompressible inflation or filling fluid canhelp rigidify the scaffold so that it maintains its shape for extendedperiods when implanted in the stomach. The expanded shape and side ofthe scaffold by itself or together with an intact portion of the devicemay form an object that is too large in all orientations, even whencompressed in peristalsis, to permit the device to pass the pylorus.

The second principal structural component may include one or moreinflatable or otherwise expandable space-occupying structures orcompartments which are secured to the interior and/or exterior of theexpandable scaffold. The space-filling structures or compartments assumea space-filling configuration when inflated or otherwise filled orexpanded, typically being inflated or filled at least partly with acompressible fluid, typically a gas such as air. Such filling orinflation of the scaffold and/or the space-filling compartment(s) may beaccomplished from an external pressurized fluid source, but certaingaseous inflation media can be generated in situ within the component bychemical reactions induced by mixing reactants or otherwise initiating agas-producing chemical reaction. In some cases, the scaffold may formall or a portion of the space-filling structure or compartment.

The gastric balloons, as described herein, may comprise two or morewalls or layers or lamina of materials to improve the durability of thedevice by optimizing the performance characteristics of differentmaterials. This is desirable because the maximal thickness of the entiredevice in its deflated state such that it can be passed uneventfullythrough the esophagus is limited and is useful even for a simple, singlecompartment balloon. Typically, the outermost layer is made ofmaterials, such as silicone rubber, selected primarily for theirbiocompatibility in the stomach and resistance to an acidic environmentand the innermost layer is made of materials selected primarily fortheir resistance to structural fatigue and permeability to the fillingfluid. In addition, use of multiple layers allows the layers to beformed from different materials having different properties, to enhancethe performance characteristics of the entire balloon structure. Theinner layers could have biocompatibility of a shorter duration than theoutermost layer. It may be desirable to enhance the durability furtherby embedding other structural elements in the layers, such as a meshmade of metal, polymer, or high strength fibers, such as Kevlar®. In thesimplest embodiment, the two layers are either bonded together tofunction as a single wall or left unbonded such that the layers couldslide by each other except at certain attachment points.

Optionally, a variety of structural elements may reside in between theoutermost and innermost layers. For support, the mesh of high strengthfibers, polymer, or metal could constitute another layer in of itselfinstead of being embedded in the layers. Alternatively, the mesh formsor is a component of the expandable scaffold. One or more layers ofmaterials selected for the optimal balance of biocompatibility,impermeability, rigidity, durability among other criteria could be addedto enhance the structural performance characteristics of the devicefurther.

The inflatable compartment(s) may be inflated with compressible fluids(gases), incompressible fluids (liquids), or in some cases mixtures ofgases and liquids. When multiple inflatable compartments are used, eachcompartment may be inflated with the same or different gas(es),liquid(s), and/or mixtures thereof. The use of gas and liquid forgastric balloon inflation has a number of advantages. A principalbenefit is the ability to control buoyancy and weight distributionwithin the balloon, e.g., by filling most of the compartments with a gasand distributing the non-gas inflation medium in other compartmentsthroughout the balloon, the risk of concentrated pressure points againstthe stomach is reduced. Second, by properly controlling the ratio of airor other gas to saline or other liquid, the gastric balloon can beprovided with a desired buoyancy and mass within the stomach. Typically,the ratio of air:liquid can be in the range from 2:1 to 10:1, morepreferably within the range from 3:1 to 6:1. Such ratios can provideeffective densities relative to water at a specific gravity in the rangefrom 0.09 to 0.5, usually from 0.17 to 0.33, depending on the totalvolume occupied by the device. Typically, the weight of the filledballoon is in the range from 50 gm to 500 gm, usually being from 50 gmto 450 gm. The use of gastric balloons which are light and less densewill reduce the risk that the balloons will cause abrasion, pressureinduced lesions, shearing lesions, or other trauma when implanted in thestomach for extended periods of time.

Optionally, gastric balloons may include at least one separatelyinflatable or otherwise expandable external bladder formed over anexterior surface of the balloon. The external bladder(s) can beseparately inflatable from both the scaffold and the space-fillingcompartment(s) although they may be attached to or share common wallswith either or both of these other principal structural components. Thebladder may be positioned on the exterior of the balloon so that it cancontrol either or both of the shape and buoyancy of the balloon as awhole. Typically, the bladder will be inflated at least partly with acompressible gas, typically air or other biocompatible gas. Often, theballoon will be underfilled, i.e., filled with a volume that does notdistend or increase the wall tension beyond that of the unfilledbladder.

The expandable scaffold, the inflatable space-filling compartment(s) orstructures, and optionally the inflatable bladder(s) may be joinedtogether in the overall gastric balloon structure in a variety of ways.Typically, each component may be separately formed and joined byadhesives, bonding, or by other non-penetrating fasteners, or by othermeans. Alternatively, all or a portion of these principal structuralcomponents may be formed by co-extrusion to provide the desiredinflatable volumes.

The external bladder(s) may also be formed from elastic and/or inelasticmaterials, such as silicone rubber and polyethylene terephthalate film(Mylar®), respectively, so that they can be inflated at the end of theprocedure to properly position the gastric balloon within the stomachand to provide for proper sizing of the balloon within the stomach. Inan illustrated embodiment, the gastric balloon includes onespace-filling compartment and one external bladder for each of the fourchannels formed by the inflatable scaffold, but the number ofcompartments and/or bladders may differ from the number of channels.

Some embodiments include at least two or more inflatable-space-fillingcompartments and in some cases may also include one or more inflatableexternal bladders. The inflation of multiple inflatable compartments andexternal bladders may be accomplished in a variety of ways. Most simply,each inflatable compartment and inflatable external bladder (if any)could be connected to an independent inflation tube which can bedisconnected after inflation. The use of multiple independent inflationtubes allows each inflatable compartment and external bladder to beselectively and independently filled, further allowing filling atdifferent pressures, with different inflation fluids, and the like. Theuse of multiple inflation tubes, however, is not generally preferredsince the tubes, collectively, can have rather a large cross section,and such multiple tubes may interfere with device deployment.

The multiple inflatable compartments and external bladders of certainembodiments may be filled through a single inflation tube in at leasttwo ways. First, by connecting the inflatable compartments and externalbladders in series, for example using a series of one-way valves,inflation through a first inflatable compartment (or external bladder)can sequentially fill additional compartments and bladders in the seriesas the pressure in each compartment raises and in turn begins to fillthe next compartment or bladder in series.

In one aspect, a selective valve system can be accessed and controlledby a single inflation tube in order to independently and selectivelyinflate each of the inflatable compartments and external bladders (ifany). Such selective valving system may be constructed in any of atleast several ways. For example, an inflation tube having a lateralinflation port near its distal end can be disposed between two, three,or more one-way valves opening into respective inflatable compartmentsand external bladders. By rotating the inflation tube, the inflationport on the tube can be aligned with one of the one-way valves at atime, thus permitting inflation of the respective compartment or bladderto a desired pressure and with a desired inflation fluid, includingliquid inflation fluids, gaseous inflation fluids, and mixtures thereof.The rotatable and selectable inflation tube could be removable.Alternatively, at least a portion of the inflation tube could bepermanently mounted within the gastric balloon structure, allowing anexternal portion of the inflation tube to be removably coupled to theinternal portion to deliver the inflation fluids.

In addition to rotatably selectable inflation tubes, the inflation tubecould be axially positionable to access linearly spaced-apart one-wayvalve structures, each of which is connected to a different inflatablecompartment or external bladder.

As a still further alternative, a single inflation tube could berotatably mounted and have several inflation ports along its lengths.Each of the inflation ports could be disposed near one, two, or moredifferent one-way valves communicating with different inflatablecompartments and/or external bladders.

The one-way valves may permit inflation by introducing an inflationmedium at a pressure sufficiently high to open the one-way valve andpermit flow into the associated inflatable compartment or externalbladder. Upon removing the pressurized inflation source, the one-wayvalve closes and remains sealed in response to the increased pressurewithin the inflatable compartment or external bladder.

The inflation tube(s) may be removable from the connected componentafter the component or multiple components have been inflated. Thus, asdescribed in more detail below, the gastric balloon may be delivered tothe stomach in a deflated, low profile configuration, typically througha gastroscope or other transesophageal delivery device. Once in place,the inflatable components may be inflated, filled, or otherwise expandedin situ to a desired volume and buoyancy typically by delivering theinflation media through the inflation tubes.

Once the desired inflation size is reached, the inflation tubes may bedetached from each of the compartments allowing self-sealing so that theinflation medium remains contained for extended periods of time. Toensure the containment of the medium, valves may be placed in series forany one or more of the inflatable component(s) and/or bladder(s). Otherexpansion protocols are described elsewhere herein. In particular,component, compartment, or portion of the balloon may be inflated insitu by inducing a gas-generating reduction within the balloon. Thereactant(s) may be present in the balloon prior to introduction to thepatient or may be introduced using the connecting tubes afterintroduction to the stomach.

Although one illustrated embodiment includes four channels in theinflatable scaffold, it will be appreciated that the present disclosurecovers gastric balloon structures having only a single passage orchannel formed within the scaffold with a single space-fillingcompartment and single external bladder. Embodiments with two channels,space-filling compartments and external bladders as well as threechannels, three space-filling compartments, and three external bladders,as well as even higher numbers will also be within the scope of thepresent specification.

The dimensions of the scaffold, space-filling compartment(s) orstructure(s), external bladder(s), and/or isolated inflation chamberswithin any or all of these components, may be selected such that thecollective volume or physical dimensions of the chambers remaininginflated after deflation of any single chamber (or limited number ofchambers) is sufficient to prevent passage of the balloon through thepyloric valve. Usually, the volume(s) will be such that at least twoinflatable components and/or chambers within said components coulddeflate without risk of the “diminished” balloon passing through thepyloric valve, preferably at least three could deflate, and often atleast four or more chambers could deflate. The precise volume(s)necessary to prevent passage of the partially deflated balloon structurethrough the pyloric valve and may vary from individual to individual. Apreferred remaining residual inflated volume may be at least about 75ml, preferably at least about 100 ml and still more preferably at leastabout 200 ml. After partial deflation, the balloon should have adimension along any axis or its cross axis of at least 2 cm, preferablyat least 4 cm, and most preferably at least 5 cm.

In one aspect, the present specification relates to methods for treatingobesity in a patient. The methods may comprise introducing a gastricballoon structure to the patient's stomach. An inflatable scaffold whichforms part of the balloon may be filled with an incompressible fluid toprovide a fixed support geometry. At least a portion of a separatespace-filling compartment may be filled at least partly with acompressible fluid, typically a gas such as air, nitrogen, or the like,within the remainder (if any) being filled with an incompressiblematerial, such as a liquid, gel, slurry, or the like. In this way, thebuoyancy of the balloon may be controlled within the limits describedabove.

The methods of the present specification may include determining thesize of the gastric cavity and selecting a gastric balloon of propersize prior to introducing the balloon to the stomach. Such sizedetermination may comprise visually examining the gastric cavity,typically under direct observation using a gastroscope, butalternatively using fluoroscopy, ultrasound, x-ray or CAT scanning, orany other available imaging method. An estimate of the dimensions of thestomach and the size of the device can be made by direct observation ofthe interior of the stomach immediately prior to deployment.Alternatively, the dimensions of the feeding stomach, which is generallylarger than the resting stomach, and the size of the device will bedetermined at an earlier session where the patient has consumed orswallowed a biocompatible filling medium, e.g., water, contrast medium,food, etc. A sufficient amount of filling medium will be consumed sothat the imaging technique can detect full relaxation of the stomachduring feeding and estimate its dimensions and size.

Introducing may include passing the gastric balloon in a deflatedconfiguration into the stomach through the same gastroscope.Alternatively, the deflated balloon could be introduced into the gastriccavity via an attachment to an orogastric or nasogastric tube. Theballoon may be oriented so that the scaffold will open with curvedgeometry conforming to the curve of the gastric cavity. The scaffold maybe released from constraint to self-expand or will be filled through aremovable inflation tube attached to the scaffold, where the inflationtube may be removed after filling. The scaffold may then be sealed or beself-sealing upon detachment of the filling tube(s) to prevent loss ofthe inflating liquid medium. Similarly, the space-filling compartment(s)may also be filled through one or more inflation tube(s) removablyattached to the compartment(s), where the tube(s) are removed after thecompartment(s) have been filled with the desired medium, for example amixture of liquid and gas sources. Further, the external bladder(s) maybe filled through one or more inflation tube(s) generally as describedabove for both the scaffold and the space-filling compartment(s).

After all the principal structural components of the gastric balloonhave been inflated or otherwise expanded and the associated inflationtubes released, any other anchors or tethers attached to the balloon mayalso be released, leaving the balloon free to “float” within thepatient's stomach. By properly selecting the ratio of liquid inflationmedium to gas inflation medium, as discussed above, the weight,distribution, and the buoyancy of the gastric balloon may be such thatthe balloon rests within the stomach without exerting undue pressure atany particular point, thus reducing the risk of abrasions or othertrauma to the stomach lining. The inflated gastric balloon may be leftin place for extended periods of time, typically as long as weeks,months, or even years.

After the balloon has been inflated and left in place, it may becomedesirable to adjust the size and/or buoyancy of the balloon for purposesof patient comfort, efficacy, or other reasons. To perform suchadjustments, the balloon may be transesophageally accessed, typicallyusing a gastroscope with suitable working tools introduced therethrough.For example, the balloon may be grasped with graspers and inflationtubes may be suitably attached or docked to inflation ports on theballoon structure. For example, the inflation ports may be located nearthe end of the gastric balloon structure which is oriented toward thetop of the stomach so that they are readily accessed through thegastroscope. After attachment with the inflation tube, the inflationmedium can be introduced and/or extracted, depending on whether theparticular structural component is to be enlarged, deflated, or have abuoyancy adjustment. Optionally, an incising instrument could beintroduced through the gastroscope to penetrate and deflate any filledcompartment to reduce the overall volume of the device and improveaccommodation of the device. Typically, these compartments are small toallow minor adjustments without jeopardizing the integrity of the deviceitself.

In addition to adjusting the size and/or buoyancy of the gastricballoon, it may become desirable or necessary to remove the ballooncompletely. To effect such removal, the balloon may be accessedtransesophageally, typically using a gastroscope. The balloon may firstbe grasped or secured using a grasping tool. Then, one or more surfacesof the balloon may be penetrated or breached in order to release thecontents of the balloon into the stomach. The contents may bebiocompatible gasses or liquids so that release into the stomach willnot be a concern. After the contents of the compartments have beenreleased, the balloon may then be pulled through the patient'sesophagus, for example by pulling with the grasping tool. It may bepossible to pull the deflated gastric balloon through the workingchannel of the gastroscope, but more often the balloon will simply bewithdrawn through the esophagus as the gastroscope is withdrawn.Optionally, a sheath or other protective cover may be placed over thedeflated balloon in order to reduce the risk of trauma or injury to theesophagus upon withdrawal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a gastric balloon having the wall breach detectionssystem of the present invention incorporated therein.

FIG. 2 illustrates a breast implant having the wall breach detectionsystem of the present invention incorporated therein.

FIG. 3 illustrates a multi-layer wall structure useful for theprostheses of the present invention.

FIG. 4 illustrates a passive transponder system which may be utilized inthe wall breach detection systems of the present invention.

FIG. 5 illustrates a hand-held interrogation unit useful with thesystems of the present invention.

FIGS. 6A through 6I illustrate leads and connectors used in electronicstimulators having the covering breach detection system of the presentinvention incorporated therein.

FIG. 7 illustrates solid device components having the wall breachdetection system of the present invention incorporated therein.

FIG. 8 is a side view of an example gastric balloon, shown deployed in astomach.

FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 8.

FIG. 10 is a top view of the gastric balloon of FIG. 8, illustrating theinflation ports or nipples.

FIGS. 11A and 11B illustrate use of example tools introduced through agastroscope for inflating and deflating a gastric balloon, respectively.

FIGS. 12A through 12E illustrate a complete deployment protocolaccording to example methods described herein.

FIGS. 13A through 13C are enlarged, peeled-back, cross-sectional viewsof a portion of the multi-layered wall of an example gastric balloonconstructed in different configurations.

FIG. 14 illustrates another example gastric balloon geometry.

FIG. 15A illustrates a first embodiment of a self-expanding scaffold forthe balloon geometry of FIG. 14.

FIG. 15B illustrates a second embodiment of a self-expanding scaffoldgeometry for a balloon having the geometry of FIG. 14.

FIG. 15C illustrates an example inflatable scaffold suitable for usewith a balloon having the geometry of FIG. 14.

FIG. 15D is a cross-sectional view taken along line 15D-15D of FIG. 15C.

FIG. 15E illustrates an example gastric balloon including a pair ofinflatable space-filling compartments contained by an external sheath.

FIG. 15F illustrates an example gastric balloon having two inflatablespace-filling compartments joined together by a spine structure.

FIGS. 16-18 are flow diagrams illustrating several valving systemssuitable for inflating gastric balloons having multiple inflatablecompartments and optionally internal bladders.

FIG. 19 illustrates an exemplary structure for valving according to FIG.16.

FIGS. 20A-20C illustrate an exemplary structure for valving according toFIG. 18.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIG. 1, the gastric balloon 100 includes two electricprobes. Probe 130 is on the external surface in contact with thesurrounding tissues, body fluids, and contents of the stomach. Probes130 and 110 can have any of a variety of shapes or configurations,including circular plates, lattices, films, and the like, cover all or aportion of the balloon or other device. Probe 110, shown here in alattice configuration, provides the second probe incorporated in thewall of the balloon. The probe material could be any metal, polymer,fiber, or combination thereof, with or without any coating that cangenerate an electrical charge or enable flow of electric current when incontact with the stomach contents. The probes are connectedelectronically to the wireless transmitter 140, but are separated fromeach other by at least one layer of non-conductive material in theballoon wall. The transmitter can be a simple wireless signal generatortriggered by an electric current or preferably is an unpoweredtransponder using well-established RFID technology which produces awireless signal in response to an interrogating signal. In the intactstate when the wall is not breached, components 130, 110, and 140comprise an open electrical circuit and the transmitter is inactive,disabled, or enabled to transmit a base signal.

Referring now to FIG. 2, a breast implant 200 may be similarly formedwith a lattice 210 formed within the breast wall, an externalelectrically conductive probe 230 formed on or over the exterior surfaceof the implant, and a transmitter 240 connected to both the lattice andexterior probe. In the case of breast implants filled with lowconductivity materials, such as silicone gel, it may be desirable toprovide conductive materials to enhance conductivity upon leakage.

As magnified in FIG. 3, the second internal probe comprises both a finelattice 110 and a thin film configuration 112 in the wall of the balloonin between, at the minimum two layers, an outermost layer 102 andinnermost layer 104. The second internal probe can be also disposed inany enclosed space in the device (not shown). In the configurationdescribed in FIG. 1, probes 130 and 110 and transponder 140 representone open circuit and probes 130 and 112 and transponder 140 represent asecond open circuit. Each open circuit is available to power or enablethe transmitter or may enable the transponder to alter a base signal.

After the balloon is deployed in the stomach, the external probe 130 isin contact with the surrounding tissue and body fluids and stomachcontents. Upon a breach in the integrity of the wall, such as a tear inthe outermost layer 102, the leakage of physiologic fluid or stomachcontents with electrolytes into the tear forms a salt bridge that closesthe circuit formed probes 130 and 112 and transponder 140. Once thecircuit is closed, a toggle is switched in the transponder, which willbe enabled to transmit a “layer 102 breach” signal. Tears through layer106 in the balloon wall will allow leakage of physiologic fluid orstomach contents with electrolytes into the tear forming a salt bridgethat closes the circuit formed probes 130 and 110 and transmitter 140.Closing this circuit switches another toggle in the transponder, whichwill be enabled to transmit a “layer 106 breach” signal.

The preferred radiofrequency identification circuit is shownschematically in FIG. 4. The circuit comprises a transmitter component300 which includes transponder circuitry 302, typically formed as anintegrated circuit, and a tuned antenna-capacitor circuit 304. Aninterrogator reader 310 comprises circuitry 312 including the powersupply (typically a battery) demodulator circuitry, decoder circuitry,and the like. An antenna 314 is tuned so that it can communicatewirelessly with the antenna 304 of the transponder 300. Operation ofthis circuitry is generally conventional and provides for energizing,demodulating, and decoding signals between the external and implantedcomponents. The transponder circuitry, however, will be modified so thatthe conductive elements implanted in the wall, such as film 320 andlattice 330 may enable or alter the signal emitted by the transponderwhen the conductive elements are bridged by body fluids or inflationmedium. In the preferred embodiments described above, electricalcoupling of the conductors 320 and 330 will alter the signal that isproduced by the transponder 302. In that way, the patient or other userwill be able to interrogate the transponder and receive a base or“normal” response signal when no wall breach has occurred. In the eventof a wall breach, the signal emitted by the transponder will be alteredso that the breach will be made evident.

An exemplary reader module 120 is shown in FIG. 5 and includes LEDs toindicate normal or “on” function, failure, and emergency failure. Anaudible the alarm 126 could also be provided to alert with beepingsounds, or sensory, such as vibrations, or preferably a combination ofany or all of the above. Optionally, the detector could have differentauditory, visual, sensory, or different combinations to identify thesource of the detected breach, especially with more than one chemicalsubstance used. The alarm could further indicate the seriousness of thebreach. For example, when breaches are detected, the volume of the alarmwould increase to a higher level.

Referring now to FIG. 6A, an electrical lead 600 with a functionalconductor 650 which is useful for cardiac or neuro stimulators may besimilarly formed with an electrically conductive lattice 610 embeddedwithin an insulating covering 605, an external electrically conductivecable coil 630 attached to the exterior surface of the implant, and atransmitter 640 connected to both the lattice 610 and external coil 630.As shown in the cross section FIG. 6B, the lattice 610 is preferablyformed coaxial to the conductor 650 and separated from the conductor andthe surrounding environment by inner and outer annular portions of thecover 605. The cross section of FIG. 6C shows conductive probes 610 and620 in lattice form both embedded in the covering. The cross section ofFIG. 6D shows a plurality of conducting probes 610 and 620 which areembedded coaxially in the insulating covering 605. In this embodiment, acurrent flow enabled by electrolytes between external probe 630 and 610or 620 or the functional conductor 650 could indicate the extent of thebreach. An alternative configuration is shown as lead 601 in FIG. 6E andFIG. 6F with two functional conductors 650 a and 650 b connected attheir ends but electrically isolated from each other along their lengthso that each can serve as a backup for the other. In this configuration,the probes 610 and 620 do not have to be separated from but are incontact with the functional conductors.

In the case of detecting a breach of the functional conductor, a lead602 is shown with two electrically conductive probes 660 and 670 coupledto two ends of the functional conductor 650, as shown in FIG. 6G.

In the case where the functional conductor 650 is connected to anotherfunctional electrical conductor 680, as shown in FIG. 6H, a lead 603 isshown with a transmitter 640 with two probes, 660 and 670. Probe 660 iscoupled to the functional conductor 650 and 670 to the other functionalconductor 680, in this embodiment an electrical connector. One or bothof the probes 660 and 670 are attached after the connection is made.Both probes 660 and 670 can be embedded in the functional conductorconnection housing in either the male or female side, as shown in FIG.6I. In this embodiment of a female connector 604, functional conductor650 passes through and is electrically coupled to functional conductor680. In this embodiment as electrically isolated rings inside the femaleconnector 604, probe 670 is coupled to 680 and probes 660 a and 660 bcoupled to 650. Such a configuration would enable detection of a partialdetachment of the male member 649 when the circuit between 670 and 660 bis closed but that between 660 a and 660 b is open and a possiblecomplete lead detachment when all the detection circuits are open. Theplacement and physical length of the probes 660 a and 660 b woulddetermine the amount of detachment necessary to open the circuit andenable the system to signal a breach.

While the leads and connectors incorporating the detection system areillustrated independently above, they may be configured independent toeach other in a device system or together in any combination using oneor more common detecting or signaling circuits.

Referring now to FIG. 7, two solid prosthetic device forms are shown.Cylindrical shaped 701 and a flat triangular shaped 702 are shown with atransmitter 740, an electrically conductive lattice 710, and an externalelectrically conductive probe 730, 701 a and 702 a are cross sections ofeach respectively. Any wear and tear or fracture deep to the lattice 710is detected as a breach. It can be appreciated that the principle can beapplied to a solid object of any shape. In the case of an object holdingother parts of the device in place or within a range of motion (notshown), such as functioning like a ligamentous or cartilaginousstructure in the body, respectively, detecting a breach of the objectwould indicate a potential dislocation of the other parts.

Referring now to FIGS. 8 and 9, a gastric balloon 10, in someembodiments, comprises an inflatable scaffold structure 12, fourinflatable space-filling compartments 14, and four inflatable externalbladders 16. Referring in particular to FIG. 9, the inflatable scaffold12 has a X-shaped cross-section and defines four generally axiallyoriented channels or quadrants, each of which receives one of the fourinflatable space-filling compartments 14. The four inflatable externalbladders 16 are mounted over the inflatable space-filling compartments14, and the balloon 10 includes an upper cage 18 and lower cagestructure 20 which permit grasping of the balloon using grasping tools,as will be described in more detail below. In its deployedconfiguration, the gastric balloon 10 has a crescent or curved shapewhich conforms to the interior shape of a gastric cavity, with the uppercage structure 18 oriented toward the esophagus E, the lower cagestructure 20 oriented toward the pyloric valve PV.

Referring now to FIG. 10, the inflatable scaffold structure 12 isprovided with at least one inflation port or nipple 22 while theinflatable space-filling compartments 14 are provided with a separateport 24 and the inflatable external bladders are provided with aseparate inflation port 26. Although not illustrated, the scaffold,internal components, and external bladders could have isolated,inflatable volumes therein, each of which would be attached to aseparate inflation tube. By “subdividing” the volume of the variousprincipal structural components, the risk of accidental deflation of theballoon is further reduced.

As illustrated in 11A, after the gastric balloon 10 is introduced in itsdeflated configuration into the gastric cavity, the inflatablestructural components could be inflated using a single inflation tube 30introduced through the gastroscope G, or orogastrically ornasogastrically by itself or using an orogastric or nasogastric tube.For example, the upper cage 18 can be held by a grasper 32 which canselectively hold and release the gastric balloon 12 during inflation andsubsequent deployment. Shown in FIG. 11A, inflation tube 30 can beselectively coupled to any one of the inflation ports 22, 24, or 26, andthe desired inflation medium introduced therethrough. Inflation tube 30will be suitable for delivering either liquid or gas inflation media,typically including saline, water, contrast medium, gels, slurries, air,nitrogen, and the like.

In some embodiments, the inflatable scaffold structure 12 will beinflated entirely with a liquid or other incompressible medium, such asa gel, slurry, or the like. In contrast, the inflatable space-fillingcompartments 14 may at least partly be inflated with air or other gas.Often, however, the inflatable space-filling compartments will inflatedwith a mixture of gas and liquid in order to control the buoyancy of theballoon 12. Finally, the external bladders 16 may be inflated with gasin order to provide a relatively soft outer surface which can reducetrauma and abrasion.

The various structural compartments of the balloon may be made from thesame or different materials. In some embodiments, the inflatablescaffold structure 12 will be formed from a non-distensible(non-stretching) material so that it may be inflated to become arelatively rigid structure. Alternatively, or additionally, thestructures may be formed from stiffer materials and/or be reinforced toincrease the rigidity when inflated.

In contrast, the inflatable space-filling compartments 14 and theinflatable bladders 16 may be formed in whole or in part from softerelastomeric materials in order to allow inflation flexibility, both interms of size and density of the combined inflation media. The elasticnature of the external bladders allows the peripheral dimensions of thegastric balloon to be adjusted over a significant range by merelycontrolling inflation volume. Elastic inflatable space-fillingcompartments can allow the amount of space occupied in the interior ofthe balloon to be adjusted, for example to adjust the amount of volumefilled by the balloons within the quadrants defined by the scaffoldstructure 12. Alternatively, the volume of incompressible fluidintroduced into non-elastic structures may be sufficient to control thevolume being occupied.

As an alternative to using a single inflation tube, each of theinflation ports 22, 24, and 26 could be pre-attached to separateinflation tubes. In such cases, after inflation of each structuralcomponent is completed, the necessary inflation tube could then bewithdrawn through the gastroscope G, leaving the gastric balloon 10 inplace.

Referring now to FIG. 11B, the balloon 10 can be deflated while graspingthe tip 18 of the balloon with grasper 32 through gastroscope G using ablade structure 40 introduced through the gastroscope. The bladestructure 40 may be used to make one or more penetrations or breacheswithin each of the inflatable components of the gastric balloon,including the inflatable scaffold, the inflatable space-fillingcompartment(s), and the inflatable external bladder(s)

Referring now to FIGS. 12A-5E, gastric balloon 10 may be introduced to apatient's stomach S using a gastroscope G introduced through theesophagus E in a conventional manner. Standard procedures for preparingand introducing the gastroscope are employed, including checking forulcerations in the esophagus and performing further examination ifwarranted.

After introducing the gastroscope G, the size of the gastric cavitywithin stomach S can be estimated and a balloon of an appropriate sizeselected. The balloon 10 is then also introduced through the esophagus E(orogastrically or nasogastrically) using an appropriate catheter oroptionally using the inflation tube(s) which will be used to inflate theballoon. After the entire balloon is confirmed to be in the stomach at aproper orientation, typically using the gastroscope G, the variouscomponents of the balloon 10 may be inflated as shown in FIGS. 12C and12D. First, the inflation tube 32 attached to the port which is coupledto the scaffold 12 is inflated, typically using saline or otherincompressible liquid until the scaffold structure becomes relativelyrigid, as shown in FIG. 12C. During this inflation, the balloon 10 isheld by at least an inflation tube 32 and may optionally be held byadditional inflation tube(s) and/or a grasper 32.

After the scaffold 12 has been inflated, an additional syringe is usedto inflate the space-filling compartments through a second inflationtube 33, as shown in FIG. 12D. The space-filling compartments, again,will typically be inflated with a combination of saline or other liquidand air or other gas in order to achieve the desired density of theinflation medium therein. The external bladders 16 will be inflated in asimilar manner, typically using air or other gas inflation medium only.

When it is desired to remove the gastric balloon 10, the balloon may bedeflated as previously discussed and removed through the esophagus usinga grasper 32 passing through the gastroscope G, as shown in FIG. 12E.Typically, the balloon will be pulled out using both the gastroscope andthe grasper 32.

As illustrated in FIG. 13A, the wall of a gastric balloon as describedherein includes at the minimum an outermost layer 1302 and innermostlayer 1304. The layers may be manufactured by either dipping a moldsuccessively into solutions of different materials that dry and cure orby successive precision injections of materials into a mold. Typically,the outermost layer 1302 is made of one or more materials, such assilicone rubber, selected primarily for their non-abrasiveness,biocompatibility in the stomach, and resistance to an acidicenvironment. Typically, the innermost layer 1304 is made of materialsselected primarily for their resistance to structural fatigue andimpermeability to the filling fluid. The inner layer 1304 could havebiocompatibility of a shorter duration than the outermost layer. The twolayers are either bonded together to function as a single wall or leftunbonded such that the layers could slide by each other except atcertain attachment points.

Referring now to FIG. 13B, it may be desirable to enhance the durabilityfurther by incorporating other structural elements in the layers, suchas a mesh 1306 made of metal, polymer, or high strength fibers, such asKevlar, or the scaffold (not shown). The mesh could constitute aseparate layer as illustrated in FIG. 13B or instead, could be embeddedin one of the layers of material, as shown embedded in layer 1304 inFIG. 13C. A mesh 1306 could inhibit the propagation of a tear in thelayers. Many of these materials are radio-opaque which enables imagingclearly the entire shape of the device using plain diagnostic X-rayradiography.

As illustrated in FIGS. 13B and 13C, in addition to layers of 1302 and1306, one or more layers, 1308 and 1310, of materials selected for theoptimal balance of biocompatibility, impermeability, rigidity, shearresistance among other criteria could be added to enhance the structuralperformance characteristics of the device further.

FIG. 14 illustrates an alternative crescent-shaped balloon geometrysuitable for use in the gastric balloons of the present invention.Gastric balloon 1400 has a generally flat or truncated upper surface1402 which is positioned adjacent to the esophagus E. A lower end 1404is also generally flat or truncated. These flat ends 1402 and 1404 aredistinguishable from the more tapered ends of the prior gastric balloonembodiments. Although illustrated schematically as a single unit orstructure, it will be appreciated that the balloon 1400 will usuallycomprise multiple independently inflatable space-filling compartmentsand optionally further comprise external inflatable bladders. Thegeometry shown in FIG. 14 is intended to illustrate the peripheral shapeof the device including all components.

Referring now to FIGS. 15A-F, gastric balloon structures having thegeometry of balloon 1400 in FIG. 14 may be deployed using a number ofdifferent expandable scaffolds. For example, as shown in FIG. 15A, theballoon structure 1400 may include an external “exoskeleton” 1510comprising a spine 1512 and a plurality of ribs 1514 extending laterallyfrom the spine. The spine 1512 and ribs 1514 may be made from elasticcomponents, such as nickel titanium alloys or other super elasticmaterials, permitting them to be folded and compressed to a small widthfor introduction. The scaffold will then be deployed by releasing thescaffold from constraint after it has been positioned within thestomach.

The balloon 1400 may also be mated with an end cap 1520. The end cap1520 may include, for example, a plurality of interlaced panels whichcan be folded down to a low profile configuration for delivery. Thepanels may be composed of elastic polymers, shape memory metals, shapememory polymers, or the like. The use of end caps 1520 is particularlyuseful when the balloon will itself comprise a single compartment. Theend cap will prevent accidental passage of the balloon through thepylorus even upon rapid deflation of the balloon.

The balloon 1400 may also be mated to an inflatable scaffold 1530, whichmay be conveniently formed into the shape of a saddle, as shown in FIGS.15C and 15D. The balloon 1400 may comprise one, two, or more separateinflatable compartments. Each of these compartments, as well as theinflatable scaffold 1530, may require separate inflation, preferablyusing one of the valving mechanisms described below. The inflatablescaffold 1530 could have other configurations as well, such as being inthe form of a lattice with a central inflatable spine and multiple armsdisposed laterally outwardly about the remainder of the balloon 1400.

Referring now to FIGS. 15E and 15F, the balloon 1400 may comprise firstand second internal inflatable compartments 1540 and 1542 having anexternal sheath or exoskeleton 1544. The sheath 1544 may be, forexample, a non-distensible outer tubular structure having the desiredcrescent geometry, with the inflatable compartments 1540 and 1542disposed therein. Alternatively, the exoskeleton could comprise a mesh,fabric, or other flexible containment member which holds the separateinflatable compartments 1540 and 1542 in place relative to each other.At least a portion of the exoskeleton 1544 could be made to benon-collapsible in order to prevent accidental passage of the balloonthrough the pyloric valve in case of unintended deflation of both of theinflatable compartments 1540 and 1542.

The compartments 1540 and 1542 could also be held together by a spineelement 1550, as shown in FIG. 15F. The balloons would be attached tothe spine, optionally by heat sealing or adhesives, usually one or morefasteners 1552, such as adhesive straps, are provided about theperiphery of the inflatable compartments 1540 and 1542 to hold themtogether after deployment. The spine 1550 can also optionally be used toreceive and deploy inflation tubes, as described in more detail below.

Each of the balloons 1400 described above may be provided with a valvemechanism or assembly to permit selective inflation with liquid fluids,gaseous fluids, or a combination thereof. If only a single inflatablecompartment is utilized, the valving mechanism could be simply a one-wayvalve having a connector for releasably connecting to an inflation tube.For example, the inflation tube could be connected to the connector onthe valve prior to introduction of the balloon in the patient's stomach.After introduction, the inflation medium could be introduced through thetube, and the tube detached and removed after inflation is complete.Optionally, the inflation tube could be introduced later for reinflationof the balloon if desired.

When two or more inflatable compartments, and optionally externalbladders, are provided, the valve assemblies of the present inventionmay provide for selectively delivering inflation medium to individualinflation ports on each of the inflatable compartments, externalbladders, and optionally inflatable scaffolds. Inflation valves mayinclude a one-way valve structure, such as a flap valve or a duckbillvalve. The valves associated with each compartment can be arranged topermit manipulation of an associated inflation tube so that the valve isin line with an inflation port on the inflation tube to permit deliveryof inflation medium.

In FIG. 16, for example, a first one-way valve 1600 can be mounted on awall of a first balloon compartment and a second one-way valve 1602 canbe mounted on the wall of a second balloon compartment. By thenarranging the two valves in opposite directions along a common axis, aninflation tube 1604 having a rotatable inflation port 1606 can bedisposed between the two valves. Then by turning the inflation tube, thefirst valve 1600 or the second valve 1602 may be selected to deliverinflation medium through the single inflation tube 1604.

Alternatively, as shown in FIG. 17, a first inflation valve 1610, asecond inflation valve 1612, and a third inflation valve 1614, each ofwhich is associated with a respective balloon compartment, may beaxially arranged so that a single inflation tube 1616 may be translatedto successfully access each of the one-way valves 1610. In this way,each of the associated balloon compartments may be selectively inflatedand reinflated by simply axially translating the inflation tube 1616.

As a further alternative, as shown in FIG. 18, a single inflation tube320 having multiple inflation ports 1622, 1624, and 1626 may be disposednext to a linear array of balloon compartments and one-way inflationvalves 1630, 1632, and 1634. In this way, instead of axially translatingthe inflation tube 1620, the valves can be selected by rotating the tubeso that only a single inflation port is aligned with a single one-wayvalve at one time.

It will be appreciated that the above-described valve mechanisms andassemblies may be constructed in a wide variety of ways using a widevariety of one-way valve structures. For the purposes of the presentinvention, it is desirable only that the valve structures permitselective introduction of an inflation medium to individual ballooncompartments using a single inflation tube. It will also be appreciatedthat more than one valve may be used in series (not shown) in place of asingle valve to reduce further the potential for leakage of the fillingmedia.

A first specific structure for implementing the inflation assembly ofFIG. 16 is shown in FIG. 19. The inflation tube 1604 having inflationport 1606 is disposed between a wall 1650 of a first balloon and a wall1652 of a second balloon. The first one-way valve 1600 is positionedthrough the first wall 1650, and the second one-way valve 1602 ispositioned through the second wall 1652. Those valves are shown asduckbill valves. As shown in FIG. 19, the port 1606 is aligned with thefirst one-way valve 1600 so that introduction of a pressurized inflationmedium through lumen 1605 of the inflation tube 1604 will open theduckbill valve and allow inflation medium to enter the first balloon. Bythen rotating the inflation tube 1650 by 180° so that it is aligned withthe second valve 1602, inflation medium can be similarly delivered tothe second balloon.

A specific valve system constructed generally as shown in FIG. 18 isshown in FIGS. 20A-20C. The inflation tube 1620 is rotatably disposedwithin an outer tube 1660 which passes between walls 1662 and 1664 offirst and second inflatable compartments, respectively. The distal-mostone-way valve 1634 is disposed in a first radial direction on the outertube 1660, and the next inner one-way valve 1632 is offset by 90°. Theports 1662 and 1664 on the inflation tube 1620 (FIGS. 20B and 20C notillustrated) will be arranged so that in a first rotational position oneport 1662 is aligned with one-way valve 1632 and in a second rotationalposition, a second port 1664 is aligned with one-way valve 1634. At notime, however, is more than one inflation port aligned with more thanone one-way valve on the outer tube 1660. Thus, by rotating inflationtube 1620, individual inflatable compartments can be inflated.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention which is defined by the appendedclaims.

What is claimed:
 1. A gastric balloon structure for deploying in a gastric cavity of a patient, comprising: at least two isolated non-concentric inflatable chambers, wherein each chamber of the at least two isolated non-concentric inflatable chambers has a respective inflated state volume such that deflation of any single chamber of the at least two isolated non-concentric inflatable chambers leaves the inflated state volume of the remaining chambers of the at least two isolated non-concentric inflatable chambers unaffected, and the walls of each chamber are comprised of two layers of silicone bonded to one another including an inner layer and outer layer, wherein the inner layer has a greater strength than the outer layer, and the outer layer has a greater acid resistance than the inner layer; a valve system for introducing a fluid into the at least two isolated non-concentric inflatable chambers and for retaining, upon inflation, the fluid in the at least two isolated non-concentric inflatable chambers; and a flexible member spanning a gap between and fixedly attached to both a first chamber of the at least two isolated non-concentric inflatable chambers and a second chamber of the at least two isolated non-concentric inflatable chambers, said flexible member being in fluid communication with the valve system and carrying inflation tubes that are in fluid communication with the at least two isolated non-concentric inflatable chambers; wherein the gastric balloon structure, in its inflated state, assumes a curved shape conforming to a natural three-dimensional kidney shape of the gastric cavity, such that the flexible member flexibly conforms, upon at least partially filling the at least two isolated non-concentric inflatable chambers, the gastric balloon structure to the natural three-dimensional kidney shape of the gastric cavity; and wherein, after inflation, the gastric balloon structure is configured to float freely without tethering in the gastric cavity.
 2. The gastric balloon structure of claim 1, wherein the gastric balloon structure is designed to provide for modulated passage of food through the gastric cavity upon inflation.
 3. The gastric balloon structure of claim 2, wherein the inflated state volumes of the at least two isolated non-concentric inflatable chambers are configured to leave in the gastric cavity a residual volume proximal to the gastric balloon structure unoccupied by the gastric balloon structure during a resting state of the gastric cavity, and wherein said residual volume is 10 ml to 100 ml.
 4. The gastric balloon structure of claim 1, wherein, upon inflation, the gastric balloon structure is configured to rest within the gastric cavity without exerting pressure at any point in the gastric cavity sufficient to cause ulceration.
 5. The gastric balloon structure of claim 4, wherein an outer surface of each of the isolated non-concentric inflatable chambers is configured to align against greater and lesser curvatures of the gastric cavity.
 6. The gastric balloon structure of claim 1, wherein said inflation tubes include a first inflation tube and a second inflation tube, the first inflation tube being connected by a first orifice to the first chamber of the at least two isolated non-concentric inflatable chambers, the second inflation tube being connected by a second orifice to the second chamber of the at least two isolated non-concentric inflatable chambers.
 7. The gastric balloon structure of claim 6, wherein the first orifice is oriented in a first radial direction perpendicular to a longitudinal axis of the structure and the second orifice is oriented in a second radial direction which is offset from the first radial direction.
 8. The gastric balloon structure of claim 1, wherein the gastric balloon structure is designed to maintain the inflated state volume of each of the at least two isolated non-concentric inflatable chambers while deployed in the gastric cavity of the patient without controlled adjustment.
 9. The gastric balloon structure of claim 1, wherein each chamber of the at least two isolated non-concentric inflatable chambers is filled with a same fluid.
 10. The gastric balloon structure of claim 1, further comprising a protective sheath which surrounds at least a portion of the gastric balloon structure.
 11. A gastric balloon structure for deploying in a gastric cavity of a patient, comprising: at least two isolated non-concentric inflatable chambers, wherein each chamber of the at least two isolated non-concentric inflatable chambers has a respective inflated state volume such that deflation of any single chamber of the at least two isolated non-concentric inflatable chambers leaves the inflated state volume of the remaining chambers of the at least two isolated non-concentric inflatable chambers unaffected, and the walls of each chamber comprise two layers of silicone bonded to one another including an inner layer and outer layer, wherein the inner layer has a greater strength than the outer layer, and the outer layer has a greater acid resistance than the inner layer; a valve system for introducing a fluid into the at least two isolated non-concentric inflatable chambers and for retaining, upon inflation, the fluid in the at least two isolated non-concentric inflatable chambers; and a flexible member spanning a gap between and fixedly attached to both a first chamber of the at least two isolated non-concentric inflatable chambers and a second chamber of the at least two isolated non-concentric inflatable chambers, wherein the flexible member encloses an inflation lumen for introducing the fluid into the at least two isolated non-concentric inflatable chambers via the valve system; wherein the gastric balloon structure, in its inflated state, assumes a curved shape conforming to a natural three-dimensional kidney shape of the gastric cavity, such that the flexible member flexibly conforms, upon at least partially filling the at least two isolated non-concentric inflatable chambers, the gastric balloon structure to the natural three-dimensional kidney shape of the gastric cavity; and wherein, after inflation, the gastric balloon structure is configured to float freely without tethering in the gastric cavity. 